SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '71ef0fbd63b490a61d71c3ba16866794382b675524f858e41a024ef76c99312b' 
  AND token = 'JCJBOiDsy5uvY5kR4xo4EVecrAOjJe+MzZP1/L3owx8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00048

JSON explain

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