SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f99e3e423dd44c3f2a935ba11ab07f5322c253ef82c9043088217b06ff654bd6' 
  AND token = '1PMDycS8s3kzca5S24UFqihE1W/nPIcsGRoJmkVpNWU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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