SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a4035c6756e81cacef333e84421c0de7cfe6698f0ab50123c291d4b875edf948' 
  AND token = '9E+8n8baVVIqJwcpt3ne0zFHHvSqjY7iBw5blRDUD/o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}