SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2bb80941a6e0ac7fed850ef319c8008c3edd6f4a89697baf99b094859710c280' 
  AND token = '9Enhu4muRhmdinm3Wxz4FrF40PkZAuLHNwoZA2MUMNM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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