SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '827df336c312fdcdfff6e316478ba482d97d2f5105f90909497e8779334909fa' 
  AND token = '46aRyCFmSjZpTt70wwwc3HLG3f6YgTZiLe2z+4Pkfe0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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