SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cbcc90baa90aa41338a744e4c2589878c78db9771b999d227e5fe3f941424b77' 
  AND token = 'LzAyCFEfBVlQ9QXXNSG3q++OI5pzSQCTddZpmN2N0pM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00059

JSON explain

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