SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3b535b9f629a37915bfa08a7ec2c6728fc89862c98708adda6d3cbc678f4f97c' 
  AND token = 'HRwTdTB414FCKN25efGjjUfuwc0SfdIUUteVcXSVbZo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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