SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2f3210e78afe18c7b4b342584573b7262abe10e6bcfa68542bdb815600570fde' 
  AND token = 'NnbGJbjVajRGNKmOeY2EXFBB1p1n7496wVoQ1LEfiAo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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