SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e5e61ca4ba88b569df9a48db87f65b0e857bde079e735226c47dd5e454eb31ac' 
  AND token = 'vjdwIRv+4ndIGmsDHNtHJDCX7/D/MI1+gw36yqvkgaw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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