SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e8e23ad9daaa1f090a063bb6621e86ba7f4483ae2b57bd4253157fb4e2796b38' 
  AND token = 'ERsLDciyQzYAEzEWQYlh/4pPmYrIs+rKQtzisOkq7tM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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