SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '75f1c0a73c6da23a9e88e50cf9980182a0639d2ae920be75c4b52b5b73fd9e80' 
  AND token = 'Z1l/RV7vp0Vy+KOpGQ+rX6Iof5fq4ru3oBWiz2aNOJo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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