SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '470e0a7e2a2344ce5668afe311b0443d1f6421561ed14da4c5f33d37b9fa5d83' 
  AND token = 'bbuikn9Ymuwc/YJrLkWBzJ8rYmCdKupfzi8/JqRs1fc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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