SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'db80884e9f85188d1a0536abf89e0326e5199e4fb81f917c7fbff26a0f6f5918' 
  AND token = '5OMpS0CJPo0juXXDMcG/em2m8+JXyCISTO7Tb5ytWqs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00073

JSON explain

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