SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2c6075bb65f4bb126066ba6fb91383516dd17973393735afac3b2fa516596842' 
  AND token = 'wC8vprsmWLKAF6LJHRLL36DpNen2aYZ4SdDjdyz9FGk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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