SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b5006ec2c1a81e482f470078485ed73d991ccc38d87f926cf3aa44ded5e7d055' 
  AND token = 'KRYaLrbJqaanYGSRl+vAbiQFY7fmGH+OZ23DuU4lGCE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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