SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2ee48f312425d496eb912e161cee99eb3de091fccfd6e6936d3f7ee61340fae0' 
  AND token = 'zKU8CnliodUfNoC0ObzPr3mBUpPrIaovgzyuJ/RncM4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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