SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5bbc508b3167cdb36b06572b873fc422724f5aff699b544beec2996b12288620' 
  AND token = 'pxYkySGmwu7SbvjYSB0BmMCY3AZZ6FjX8h3m8gFU3Z0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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