SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd0a8bc093b6063fecd04027f4b4d7e9ce6bcf12c91f73140ef34b4b8452b9970' 
  AND token = 'WuY36t49E0XQIrvQLR5mM+JX36WGrDet4n9qOE9na8Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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