SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c9c063716404d404017a64646f7d897a29dfd0cbfc78a96b2a63e1487bd1df6a' 
  AND token = 'EHFunrhWJHPymPHaxRZ+g4ZQwoN9mm0UcHPgdZTphDc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}