SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e53c5563afc5258f1d1c78bfacc0ddba6aa2ae276ce36846ee7fe2dc9bf7685a' 
  AND token = 'PJP1ySrdOC6blLmRlho8ql5QMvlYuip4+TGIGNAijL8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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