SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fd8e0e905accff939115b9327d4bc6a18aaf75c9cfb69960453083a2dabca140' 
  AND token = 'YWsPJ6zC0/c8H8eVnfskD/kCqQnuDSxiVtvF2Vy84Ts=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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