SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7bcfdd2aada322d3db6abc39a3357c8c4f97fa542530e43947a3809db53b4a1a' 
  AND token = 'dDGjJujZWnTsRJ4hevCx+0fGRZkDXtqWtUb+GXYarsU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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