SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '982f7ac859f63e2def88ba8e41b697ab3b70257f663ebb146fae27522de8891c' 
  AND token = 'lqaZpo2NAbQzmwigsm/YlPpNlGm+g1lSdZSW8XhBPxw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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