SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8387e2dee5dc215850f4f44b133acfa4baa3d643e2c14a1ad241324fb49ae281' 
  AND token = 'EJ7t8DUp7cTZnnUwxf0eCKPUDe8lALMGTel4wEljvCk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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