SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '636736805637a9fd2517569e49082754eb7436845cf1547d0cd6eea237e8000b' 
  AND token = 'RDwkszZQ/WDcXUmmp8WXvK5h7pMYktZJS0Fmnse1/h8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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