SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b3d3d73b392eb65ebad517d819c6932a62331a445cd87ca1c691dab66679c4f3' 
  AND token = 'YkdjQS0CTTDU+gUgNQfvmRZqY047v/TPN/wELnKyGlk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00053

JSON explain

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