SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e3d5df116f274862c6acab5f84e20be7504b49cb496f9e91089d6ccca84e19bc' 
  AND token = 'awa7vZ0Ow2k/UW2jABWWTsBGnrU80rBuh25GTyvCCmc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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