SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e9f39d89a647aa0ea746f559fcb4498439ef4e251b4d98868fe3ed3ab350abc1' 
  AND token = '7JTm1lk2VfuuwKFohgLBy8/Ch3+Mi2Zn7GCdq7tcoKA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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