SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5d141c09ac667920fcb8f8a7a846553caf144f9d1ffb05038f9e645a2da30c81' 
  AND token = 'VkFzNO/zqg1/jC95RFmeRMF9/nPa0BFNP1J+03xL55w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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