SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '77b1c45ca7fcfde836b77c0a1d112cd23f988b6bed2b11f772d7c70eef4cb199' 
  AND token = 'fpPOV+5yOtZQF5tLBEfTFQ6NOty61HjxELYXHDBNKFc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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