SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6dcb06675eec733285c3e25e51d994c496ee4b924eadb02e188841a01b56dcd9' 
  AND token = 'dL1s5HpctiXyL+wYXTFE1EkxZoJ6JLpK4MnUuYddeTM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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