SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6d155d1b19a708225299c9595b6d88b0811cd12a1a0176e8ef30e0cc10abab1a' 
  AND token = '5B6h2l638CPT1GUjUXzISh9omREF5jKaYF6nGMvN8js=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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