SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '003b606b61ff80c45109804947dadcad7e749d513e2b9819374f64dc7fd2176a' 
  AND token = 'eScPAG9H8wnJhaLB1haPCIFHEqlcOiOeFw9zhfaYVTI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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