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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a66f1d1e924def7be8a25b0299d49172f4aecae5564da5f4068d991b5a8a08ee' 
  AND token = 'BCWS7Wzupc3cuW7NuOred81caMkgCmRcRxH9+w2yR0s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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