SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2306642ba9593dddbe0e35b7479e5329e72641b3fc0f67ebb5f889d333194582' 
  AND token = 'MBOrRKjtq5epLdmBrHYGV+8ZIjm5A6Jnde/PHEyN+3k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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