SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f3453c53184912227ba508318a492df70c90c52b81218590dc032e123c73c39e' 
  AND token = 'Js5vqRMAUAXw0NxMoFChdWb3mDSVAXJmMiPi9O3CwLs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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