SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6cda375ba000a4b306939dda9ffac2a1d2ff4228bf91401e35b201f60af268bc' 
  AND token = 'jTWZan9gdW9t6Qc23mh4jS0xHxuxeiILDKrXuwFmDKM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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