SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0dbcfe62f0fd4b640539d4a91040b1bfc41585347fa3e5bb7f08f0acdf6012d2' 
  AND token = 'UxLYy6C045NMX+1QfVnJn4CsnhPdBDMLAoCpy2mbiS8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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