SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ff7e79f3e9811c5e2b38cba9b3d978c9b7a51620603f244d9ae5e258debc076e' 
  AND token = 'IcPpSxUXUv6wCNZ46vqVtgswdiNZWad8gjRbTtIg+gQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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