SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6ac1051a763fa4c4de821865cc4f34016a82bc206cc774ba3312ef3a0d9de220' 
  AND token = 'leUsgDcyuxgdQLniGubPbCkCBsXbRBalv06m5Iq3GkA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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