SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4ec347c11c3a997592ca1682c391367a6fa8422a49ef43d35260af02249a7c85' 
  AND token = 'Ry9QoiQ6RjnPHVCGyDeBrTZIqTeAunb7K+mfz3NvfrI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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