SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4c844b7743f2ef49cd587fb2b66ead5341f32b1db3144fa6e536b36342ad126c' 
  AND token = 'nn1Cvc0ZHpKPhUJEKnWCmjUGPeX0mN7wwSIVYAiwut4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}