SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bb98b3ff92f32e3317d4e31269bff694d64ae3b6f88dedf443e425277e68ea67' 
  AND token = 'kQPhdSQ0qpPcimif2WqZsjfjr4/tkIiGl0YgzFTwMVk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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