SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3bd47731d18c17b2b04364af280449b0aaba042a06990a60dbf67b644cdc6aa5' 
  AND token = 'FDOhj68DN30Cton+0ScCrKb1P1c4VGrsdpv5jBTLpXk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00012

JSON explain

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