SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8a94a007a114a2a5a61eafafb91a96ad141fc89608a0bcd44d3b477edd2c45e3' 
  AND token = 'GZmV1vqugWc8ITPVcU2w4SIPi068eUmIHHjfEHHjdQk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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