SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '42b2d3554a4b93c0ef805fbdb8af841388ce1113d3bda810f9323ff7f9444575' 
  AND token = 'f7iqTMe+C62pyRns3EEA9z4vvYYCg+WjswlIlDwr2TU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}