SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'de181bd44f955d1c227d3964e05ecf1baddf89c8de4abc283536a5fb0a059e99' 
  AND token = '7lBzpdv/apPvqyqseq8anD309KR1R3BvyDiWP+uqm0M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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