SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f8154e20afe4d2eb8a2ac5e3dbee4926760260e408db575d0c2770081375759a' 
  AND token = 'DEoEhV6ZKD2sYx2VdNVhxaxCPobLihZc7I/dN923oXM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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