SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'de38285cc53bc8134003a7a4dfc945abef331b35e2469b42a8becef531e5e5bd' 
  AND token = 'o6G+lDpsOi4Md8ZznsxDNBwjSPKkBcDvJBkmzVyYPyQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}