SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5a3350eae3c77d490a62515dfbbba710015951eff0efdf87ab4292cca71df340' 
  AND token = 'iIDQHzazw+Us8tDTe0FdHliBazb0a1TQAgIuIVReQyk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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