SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ba50cdb5020f7604ed86a27836e53c364aa73b2f4cec43b2932462b7ad49d797' 
  AND token = '4YBo6FgXdLqVpXBQjkWhY+rldF7vB6uEudVy5Gf5ugI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.01235

JSON explain

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