SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '082beaa312f92a5971b7ab346acba41ad0a38b1bba657305e7d42c0c342df797' 
  AND token = 'SNny3EF3IpSyU+nVVp4sFCb1hGqtSeZ8q0u9aJakWHI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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