SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f0684c39810119f39b774ccab5ad3eb8285e2568136a5eb2ff1bac37bd430ed7' 
  AND token = 'UoxhDWLSjm9HcTlTmUZVM6XZxP+l9k2a/5wejdyMwYo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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