SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4ad2e55a55410af4b0f06f8cf42fad6f33bd3347256a26ff103759c0fd70fee2' 
  AND token = 'Fn1VWj/83PPlccsM16ftyccZ0TuqBHoS4Kk1yEMN7IY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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