SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '20e20c61121ed746cf1f84c65ab5e61985adf102f3f81a89db5a0b7b9bade5be' 
  AND token = 'gg1t3VQ/pGNStZxyyhwLRiyQ1nNMb+2HEvxKxfJhVLw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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